1. Field of the Invention
The present invention relates to a liquid jetting apparatus and a piezoelectric actuator.
2. Description of the Related Art
There has been conventionally known a liquid jetting apparatus having a piezoelectric actuator which applies jetting energy to a liquid. For example, there has been known an ink-jet head including a channel forming substrate in which a plurality of pressure chambers, which are communicated with a plurality of nozzles respectively, are formed and a piezoelectric actuator provided in the channel forming substrate.
One piezoelectric actuator includes a plurality of piezoelectric elements, which are arranged on the surface of an elastic film covering the pressure chambers formed in the channel forming substrate so as to face the pressure chambers, respectively. Further, a seal substrate is provided in the channel forming substrate to cover the piezoelectric elements and the piezoelectric elements are hermetically sealed by the seal substrate.
In the channel forming substrate, there are formed a plurality of lead electrodes which are drawn from the piezoelectric elements to the outer side of the seal substrate, respectively. Further, a driver IC for driving the piezoelectric elements is installed on the seal substrate. The lead electrodes are connected to the driver IC by wires individually (wire bonding).
In the above ink-jet head, the driver IC installed on the seal substrate covering the piezoelectric elements is connected to the lead electrodes drawn from the piezoelectric elements by the wire bonding. However, the connection by the wire bonding is actually troublesome. Especially, in a case that the lead electrodes, which are drawn from many piezoelectric elements respectively, are disposed densely in association with the high density arrangement of the nozzles of the ink-jet head, it is not easy to connect the wires to the lead electrodes one by one and the reliability of conduction declines eventually.